CRYSTENGCOMM
·
2014
·Vol. 16
·期 37
·8910-8916
·
IF 3.858
Feng Ye,Hui Liu,Wenlai Huang,Jun Yang
Controlling the morphology of noble metal nanoparticles can be an effective way to produce nanomaterials with favourable properties. Herein, we report our study on the effects of diffusion rate and reaction kinetics on the morphology of a number of noble metal (Au, Ag, Pd, and Pt) nanoparticles. A glass reactor based on electrochemical reduction or photo-reduction has been designed to achieve control of diffusion and chemical reduction of the different noble metal precursors. The results show that the noble metal nanoparticles with flower-like, core–shell, or wheel-like morphologies could be obtained at a relatively high diffusion rate due to the presence of additional growth of metal precursors on the preformed metal nuclei, while at relatively low diffusion, the as-prepared noble metal nanoparticles are small and quasi-spherical due to the relatively fast reduction of metal precursors. The experimental observations are also confirmed qualitatively by kinetic Monte Carlo (kMC) simulations. Since diffusion and reaction kinetics are universal and key factors in the synthesis of nanomaterials, the findings in this work might provide an effective way to manipulate the morphology of nanomaterials for a given application.
研究领域:
纳米材料科学
·
物理化学
·
材料合成
·
胶体与界面化学
·
计算材料学
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED MICROBIOLOGY
·
2019
·Vol. 126
·期 1
·127-137
·
IF 2.683
Zhang H.‐L.,Zhang C.,Pei C.‐H.,Han M.‐N.,Li W.
AimsWe aimed to explore Yarrowia lipolytica carbonyl reductases as effective biocatalysts and to develop efficient asymmetric reduction systems for chiral alcohol synthesis.Methods and ResultsYarrowia lipolytica carbonyl reductase genes were obtained via homologous sequence amplification strategy. Two carbonyl reductases, YaCRI and YaCRII, were identified and characterized, and used to catalyse the conversion of 2‐hydroxyacetophenone (2‐HAP) to optically pure (S)‐1‐phenyl‐1,2‐ethanediol. Enzymatic assays revealed that YaCRI and YaCRII exhibited specific activities of 6·96 U mg−1 (99·8% e.e.) and 7·85 U mg−1 (99·9% e.e.), respectively, and showed moderate heat resistance at 40–50°C and acid tolerance at pH 5·0–6·0. An efficient whole‐cell two‐phase system was established using reductase‐expressing recombinant Escherichia coli. The conversion of 2‐HAP (20·0 g l−1) conversion with the solvent of dibutyl phthalate was approximately 70‐fold higher than in water. Furthermore, the two recombinant E. coli displayed biocatalyst activity and enantioselectivity towards several different carbonyl compounds, and E. coli BL21 (DE3)/pET‐28a‐yacrII showed a broad substrate spectrum.ConclusionsA new whole‐cell recombinant E. coli‐based bioreduction system for enantiopure alcohol synthesis with high enantioselectivity at high substrate concentrations was developed.Significance and Impact of the StudyWe proposed a promising approach for the efficient preparation of enantiopure chiral alcohols.
研究领域:
生物化学
·
生物技术
·
酶学
✓ 已验证
DOI
PubMed
高影响因子
CHEMISTRY-A EUROPEAN JOURNAL
·
2019
·Vol. 25
·期 10
·2637-2644
·
IF 5.16
Yanqiang Li,Huiyong Huang,Siru Chen,Chao Wang,Tingli Ma
Graphical Doped to reduce : FeN x -decorated carbon nanotubes are prepared by utilizing ZnO nanowires as a sacrificial template and Fe–polydopamine (Fe–PDA) complex as metal and carbon sources (see figure). The evaporation of Zn at high temperature results in a high surface area of the carbon nanotubes, and the FeN x species contribute greatly to the oxygen reduction reaction activity of the catalyst. It is of increasing importance to develop highly active and economical oxygen reduction reaction (ORR) electrocatalysts, which have great significance for the large-scale implementation of various energy conversion systems, including metal–air batteries and fuel cells. Herein, a novel method to synthesize FeN x -decorated carbon nanotubes as a high-efficiency ORR catalyst, by utilizing ZnO nanowires as a sacrificial template and a Fe–polydopamine complex as metal and carbon sources, is reported. The obtained catalyst shows great potential for replacing Pt/C as the ORR catalyst under various pH conditions, from alkaline to acidic electrolytes. The high conductivity, large surface area of the carbon nanotube, and highly active FeN x species contributed greatly to the high performance of the catalyst. The work presented herein paves a new way for the synthesis of 1D porous nanomaterials for a broad range of energy-related applications.
研究领域:
材料科学
·
电化学
·
能源技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2018
·Vol. 44
·期 7
·8710-8715
·
IF 3.057
Yang Chen,Chengji Deng,Chao Yu,Jun Ding,Hongxi Zhu
ZrN nanopowders were obtained by using ZrO 2 and Mg as the main raw materials in a molten salt environment and a high-purity nitrogen atmosphere. The effects of ZrO 2 / Mg mole ratio, nitriding temperature , and holding time on the synthesis of ZrN were investigated. ZrN was formed at 700 °C for 3 h. When the nitriding temperature increased to 1000 °C, pure phase ZrN was formed. The specific surface area of ZrN was 20.92 m 2 /g. When the temperature rose to 1100 °C, the resulting ZrN particles were finer; the average size of ZrN decreased from 71.60 to 49.65 nm. Further, an excessively long holding time led to evaporation of the molten salt, ZrO 2 , which was not fully nitrided. Finally, a possible formation mechanism of ZrN is proposed.
研究领域:
材料科学
·
无机化学
·
纳米材料
·
高温合成
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2014
·
IF 4.086
Hongjiao Nie,Yining Zhang,Wei Zhou,Jing Li,Baoshan Wu,Tao Liu,Huamin Zhang
The direct effect of nitrogen content and various nitrogen species on oxygen reduction reaction (ORR) activities in non-aqueous lithium-oxygen (Li-O 2 ) batteries are systematically investigated. Mesoporous carbon (MC) with various nitrogen species is prepared through heat treatment of N-containing precursor under different temperature. The effect of the heat treatment temperature on the performance of carbon materials in Li-O 2 battery is investigated. The bonding state of nitrogen atoms is found to have a significant effect on the ORR activity. The ORR activity in Li-O 2 battery is proved to be dependent on the quaternary N content while the total N content in the carbon material does not play a crucial role in the ORR process.
研究领域:
电化学
·
能源材料
·
纳米材料
·
电催化
·
锂离子电池
✓ 已验证
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2019
·
IF 6.97
Mingli Zhang,Hengcong Tao,Yongchao Liu,Chao Yan,Song Hong,Justus Masa,Alex W. Robertson,Shizhen Liu,Jieshan Qiu,Zhenyu Sun
Development of naturally abundant, low cost, and energy-efficient electrocatalysts for the oxygen reduction reaction (ORR) is essential for commercialization of fuel cells. In this work, we report simple ultrasonication assisted synthesis of nitrogen and boron dual-doped graphene oxide (NB/GO) and demonstrate its application as an effective ORR catalyst realizing predominantly 4e– reduction of O2 to OH– in 0.1 M KOH. Enhanced ORR electrocatalysis of the dual B and N codoped GO as opposed to GO singly doped with B or N arises from the synergistic interaction of the boron and nitrogen species. The content and configuration of both N and B dopants can be readily tailored by controlling the ultrasonic conditions, thereby permitting tuning of the ORR activity. Furthermore, the developed NB/GO metal-free catalyst exhibited very promising long-term durability and resistance to methanol poisoning compared to the state-of the art Pt/C catalyst.
研究领域:
材料科学
·
电化学
·
能源技术
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2015
·Vol. 36
·期 2
·204-208
·
IF 1.964
Zhongkui Zhao,Renzhi Li,Yu Li,Guiru Wang
A clean and highly efficient catalytic aerobic reductive ring-cleavage of 3–methylanthra[1,2- c ]isoxazole-6,11-dione to 1-amino-2-acetylanthraquinone was performed using simple organic amines as organocatalysts and water as a green reaction medium. This method provides a new clean transformation of isoxazole-containing compounds to the corresponding ortho -amino ketones . The catalytic performance of various organic amines was carefully screened, and simple organic primary amines were found to be promising practical catalysts with outstanding catalytic performance. Isopropylamine as the organocatalyst gave 97.2% conversion of 3–methylanthra[1,2- c ]isoxazole-6,11-dione, with 97.2% selectivity to 1-amino-2–acetylanthraquinone, in the presence of oxygen only, using 1 equiv. of hydrazine hydrate at room temperature for 3 h. A possible mechanism is also proposed.
研究领域:
有机化学
·
催化化学
·
绿色化学
·
药物化学
·
合成方法学
✓ 已验证
DOI
高影响因子
FOOD CONTROL
·
2014
·
IF 2.819
Chunmei Jiang,Junling Shi,Xianqing Chen,Yanlin Liu
Fungal profiles and ochratoxin A (OTA) accumulation during wine making were investigated using five different wine grape cultivars, Cabernet Sauvignon, Pinot Noir, Merlot, Syrah and Petit Verdot and the intrinsic influences caused by sulfur dioxide, ethanol and combine effect of ethanol and reducing sugar were analyzed using Cabernet Sauvignon and inoculation of Aspergillus carbonarius . Aspergillus spp. and Penicillium spp. were found as the major fungi in all winemaking processes and were highly correlated with OTA accumulation in wine. Most fungi died and OTA production decreased after 48 h of alcoholic fermentation , being consistent with the period when ethanol accumulation increased. The addition of SO 2 significantly inhibited the growth and OTA production of A. carbonarius with complete inhibition at 500 mg/L. When the ethanol concentration in the must increased to the range of 2–4%, growth and OTA production of A. carbonarius were significantly inhibited. Reducing sugar concentration had no significant effect on the growth and OTA production of A. carbonarius within the levels changing during the winemaking. Therefore, the increase of ethanol concentration played an important role in causing the decrease of fungal contamination and OTA accumulation during winemaking.
研究领域:
食品微生物学
·
真菌毒素学
·
酿酒科学
·
食品安全
·
应用微生物学
·
分子毒理学
✓ 已验证
DOI
高影响因子
Journal of Cleaner Production
·
2019
·
IF 6.395
Duchao Zhang,Hongbin Ling,Tianzu Yang,Weifeng Liu,Lin Chen
Electric arc furnace (EAF) dust is a hazardous waste material containing valuable elements, such as zinc (Zn) and iron (Fe), as well as other environmentally harmful elements. In the conventional process, the existence of zinc ferrite (ZnFe 2 O 4 ) in EAF dust results in a low recovery ratio of zinc and can induce high energy consumption or difficulties utilizing iron resources. In this article, a hydrothermal reduction method in a NaOH system is proposed to recover Zn selectively from EAF dust. First, when pure ZnFe 2 O 4 was used as the input material to test the feasibility of the new method, 70% Zn leaching efficiencies and the isolation of Fe in the residue through the formation of ferroferric oxide (Fe 3 O 4 ) were achieved at the optimal conditions of 260 °C, 6 M [NaOH], 10 g/L [C 6 H 12 O 6 ] n and 50 mL/g of L/S. Second, a leaching process of EAF dust was proposed using the following two procedures: (i) first leaching under normal pressure to dissolve zinc oxide (ZnO); and (ii) second leaching of the first leach residue under hydrothermal reduction conditions to dissolve ZnFe 2 O 4 . The leach liquor from the second step was recycled to the first step. Under optimum conditions, the leaching efficiencies of Zn during the first and second leaching were 66.4% and 69.3%, respectively. The total Zn leaching efficiency was calculated to be 89.7%, producing Zn-impregnated leach solution and a leach residue rich in Fe (up to 39.4 wt%) that are suitable as resources for a steel-making plant. However, this process also has its shortcomings owning to larger liquid-solid ratio in the leaching process. Overall, the study technically provides an alternative approach to improve the recycling of zinc and iron and effectively reduce environmental risks from EAF dust.
研究领域:
环境工程
·
冶金工程
·
资源循环利用
·
清洁生产技术
·
工业废物处理
✓ 已验证
DOI
高影响因子
Nano Energy
·
2016
·
IF 11.553
Zhaoqiang Li,Caixia Li,Xiaoli Ge,Jingyun Ma,Zhiwei Zhang,Qun Li,Chengxiang Wang,Longwei Yin
Reduced graphene oxide (RGO) wrapped metal-organic frameworks (MOFs) derived cobalt doped porous carbon polyhedrons synthesized via a carbonization process, are for the first time used for sulfur immobilizers (RGO/C–Co-S) as cathodes for high performance lithium-sulfur (Li–S) batteries. The RGO/C–Co–S cathode exhibits greatly improved electrochemical performance, showing excellent specific capacity of 949 mAh g −1 at 300th cycle at a current density 0.3 A g −1 , displaying enhanced rate capability with specific capacity of 772, 704 and 606 mAh g −1 at current density of 0.5, 1 and 2 A g −1 , respectively. The synergetic effect of MOFs-derived porous carbon, homogeneously distributed Co nanoparticles and RGO nanosheets simultaneously contributes to the confinement of sulfur species. The presence of abundant mesopores and micropores is conducive to immobilize large amounts of S species. The homogenously inlaid ultrafine Co nanoparticles can further immobilize sulfur by chemical interactions between Co and S/polysulfides. The RGO nanosheets tightly wrapped on carbon hosts act as barrier layers to prevent polysulfides from diffusing out of the matrix, further suppressing shuttle effect. The porous structure and the RGO can effectively alleviate the volume changes resulted from charge–discharge process. This design strategy can be inspiring for MOF-derived materials in energy storage applications .
研究领域:
材料科学
·
电化学
·
能源存储
·
纳米材料
·
电池技术
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2018
·Vol. 6
·期 24
·11370-11376
·
IF 9.931
Qinglong Fu,Pan Yang,Jingchuan Wang,Hefang Wang,Lijun Yang,Xiaochong Zhao
Simple, safe and economic methods to prepare Ni nanofibers are required for their practical application. Herein, an in situ vacuum thermal reduction strategy is proposed to synthesize Ni nanofibers on a large scale, which involves electrospinning of a nickel acetate/polyvinylpolypyrrolidone/ethyl cellulose (NiAc/PVP/EC) precursor solution, followed by vacuum thermal treatment. Characterization of the morphology and microstructure reveals that the as-prepared Ni nanofibers are composed of nano-size Ni grains and possess a large surface area. Moreover, it has been demonstrated that the content of EC is closely related to the size of Ni grains and thus the surface area of Ni nanofibers. On account of their high specific surface area, the as-prepared Ni nanofibers exhibit efficient catalytic properties for H2 generation from hydrous hydrazine in an alkaline solution.
研究领域:
材料科学
·
纳米技术
·
催化化学
·
能源材料
·
物理化学
✓ 已验证
DOI
高影响因子
INTERNATIONAL BIODETERIORATION & BIODEGRADATION
·
2017
·
IF 2.962
Ee Li,Jiajia Wu,Dun Zhang,Yan Sun,Juna Chen
D-phenylalanine (D-Phe) was tested for its effect on the corrosion of Q235 carbon steel caused by Desulfovibrio sp. which belongs to sulfate reducing bacteria (SRB). Weight loss results indicated that the corrosion rate of Q235 coupons exposed to D-Phe was reduced. Much less pits were found on the surface of these coupons. It was found that pH and dissolved oxygen content of bacteria cultures as well as the growth of bacteria were not affected by D-Phe. However, the cell shape of D . sp. was changed to a more filamentous or spherical shape by treatment with D-Phe, and the structure of biofilms formed by bacteria with transformed shapes was looser and thinner. Moreover, the hydrogen sulfide production of D . sp. was inhibited by D-Phe. These results suggest that D-Phe may inhibit the corrosion process through two ways, i, D-Phe alters the bacteria shape, which inhibits the formation of biofilm and changes the structure of it consequently; ii, D-Phe reduces the production of hydrogen sulfide .
研究领域:
微生物腐蚀
·
材料科学
·
环境微生物学
·
金属腐蚀与防护
·
生物膜研究
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）